BRESENHAM'S LINE
DRAWING
ALGORITHM
INTRODUCTION-
• THE BRESENHAM ALGORITHM IS A INCREMENTAL SCAN CONVERSION ALGORITHM.
• THE BIG ADVANTAGE OF THIS ALGORITHM IS THAT, IT USES ONLY INTEGER CALCULATIONS.
• dlower. =y−yk
=m(Xk+1)+b−Yk
• dupper. =(yk+1)−y
=Yk+1−m(Xk+1)−b
• dlower−dupper=2m(xk+1)−2yk+2b−1
• dx(dlower − dupper) =dx(2dydx(xk+1)−2yk+2b−1.
=2dy.xk−2dx.yk+C
• Pk=2dy.xk−2dx.yk+C
• Pk+1=pk+2dy−2dx(yk+1−yk)
• P0=2dy−dx
ALGORITHM-
1) INPUT END-POINTS OF THE LINE (X1 ,Y1 ,X2 ,Y2)
2) X = X1 AND Y = Y1
3) CALCULATE DX AND DY
4) PO = (2*DY) - DX
5) IF PK <0
PLOT(XK+1 , YK) SET PK+1= PK + (2DY)
ELSE
PLOT(XK+1 ,YK+1) SET PK+1= P+(2DY)-(2DX)
1) REPEAT STEP 5 (DX) TIMES.
2) END
Draw a line from (20,10) to (30,18)-
dx = (30-20) = 10
dy = (18-10) = 8
Po = (2*dy) - dx
=16-10 = 6
k Pk Plotted pixel (x,y)
0 6 (21,11)
1 2 (22,12)
2 -2 (23,12)
3 4 (24,13)
4 10 (25,14)
5 6 (26,15)
6 2 (27,16)
7 -2 (28,16)
8 14 (29,17)
9 10 (30,18)
THANK YOU

Bresenham's line drawing algorithm

  • 1.
  • 2.
    INTRODUCTION- • THE BRESENHAMALGORITHM IS A INCREMENTAL SCAN CONVERSION ALGORITHM. • THE BIG ADVANTAGE OF THIS ALGORITHM IS THAT, IT USES ONLY INTEGER CALCULATIONS.
  • 3.
    • dlower. =y−yk =m(Xk+1)+b−Yk •dupper. =(yk+1)−y =Yk+1−m(Xk+1)−b • dlower−dupper=2m(xk+1)−2yk+2b−1 • dx(dlower − dupper) =dx(2dydx(xk+1)−2yk+2b−1. =2dy.xk−2dx.yk+C • Pk=2dy.xk−2dx.yk+C • Pk+1=pk+2dy−2dx(yk+1−yk) • P0=2dy−dx
  • 4.
    ALGORITHM- 1) INPUT END-POINTSOF THE LINE (X1 ,Y1 ,X2 ,Y2) 2) X = X1 AND Y = Y1 3) CALCULATE DX AND DY 4) PO = (2*DY) - DX 5) IF PK <0 PLOT(XK+1 , YK) SET PK+1= PK + (2DY) ELSE PLOT(XK+1 ,YK+1) SET PK+1= P+(2DY)-(2DX) 1) REPEAT STEP 5 (DX) TIMES. 2) END
  • 5.
    Draw a linefrom (20,10) to (30,18)- dx = (30-20) = 10 dy = (18-10) = 8 Po = (2*dy) - dx =16-10 = 6 k Pk Plotted pixel (x,y) 0 6 (21,11) 1 2 (22,12) 2 -2 (23,12) 3 4 (24,13) 4 10 (25,14) 5 6 (26,15) 6 2 (27,16) 7 -2 (28,16) 8 14 (29,17) 9 10 (30,18)
  • 6.